This invention relates to an infusion instrument for use in vitrectomy and in particular relates to an infusion instrument having an illumination unit for illuminating the inside of an eyeball.
FIGS. 21 and 22 show a conventional operation condition in which a prior art infusion instrument is used in vitrectomy, for instance, in order to cut an opaque portion of the vitreous between a lens 1p and a retina 2p so as to be replaced with a transparent liquid such as intraocular irrigating solutions whereby light can properly reach the retina 2p through the lens 1p or in order to cut a tissue proliferation formed in front of the retina 2p so that light can properly reach the retina 2p.
It is well-known that infusion, cutting, suction and illumination are indispensable to vitrectomy. In a conventional operation, a cutter 4p and a tool 5p are inserted into the scleral 7p of the eyeball 3p at a distance of about 4 mm from the limbus cornea 6p. The cutter 4p has a passage for the suction purpose therein. The tool 5p has an infusion tube 8p and a plurality of optical fibers 9p for the illumination purpose as shown in FIG. 22.
In operation, the cutter 4p and the tool 5p are held by hands, respectively. While the light from the optical fibers 9p illuminates the inside of the eyeball 3p, an opaque portion of the vitreous body 10p is cut by the cutter 4p. At the same time, the intraocular irrigating solution is infused into the eyeball while the cut portion is sucked through the passage of the cutter 4p to the outside of the eyeball 3p. A predetermined intraocular pressure in the eyeball 3p can be maintained by the intraocular irrigating solution.
In the conventional infusion instrument, however, the sectional area of the tool 5p must be large because the plural optical fibers 9p are arranged around the infusion tube 8p. Thus, collapse of the eye is apt to take place when the tool 5p is drawn out from the eyeball 3p.
If the tool 5p is set small in section, then the inside of the eyeball is not illuminated to a desired degree, and a sufficient volume of intraocular irrigating solution does not flow through the infusion tube 8p.